This is a transnational history of the early republic that focuses on religious actors. The early American foreign mission movement was an outward-looking expression of the benevolent network of the early republic. Building on transatlantic connections that predated the American Revolution, it represented American evangelicals’ attempt to transform the “heathen world” into part of God’s kingdom. Using ABCFM missions to in India, the Cherokee Nation, and Liberia as case studies, this dissertation examines the relationship between the church and imperial politics. In the 1800s, Americans, who had focused their evangelism on Native Americans, joined British evangelicals in the work of world mission. In the first decades of their work, they saw the potential of imperial expansion as a conduit for evangelization. In practice, evangelicals found great faults with imperial governments. Everywhere, missionaries struggled to determine how linked the projects of Christianizing and “civilizing” ought to be. With regard to gender norms in particular, missionaries found the introduction of “civilization” to be an essential part of their work. The question of slavery ultimately led to a shift in mission policy. By the mid-1840s, the Board insisted that it was a single-issue organization whose sole purpose was the conversion of the world. In so doing, the Board shifted away from the early 19th century model of foreign missions as bearers of “civilization” to a mid-19th century model of a separation between missions and politics.